Wireless communication method, user equipment and enode b

ABSTRACT

Provided are wireless communication methods, a UE and an eNB. The wireless communication method performed by a UE includes transmitting transport block repetitions to an eNB, wherein one HARQ process includes multiple repetition sets of a transport block if one repetition set of the transport block is not enough for the eNB to successfully decode the transport block, each of the multiple repetition sets includes multiple repetitions of the transport block, each of the multiple repetition sets is followed by a feedback channel to indicate whether the transport block is successfully decoded by the eNB.

BACKGROUND

1. Technical Field

The present disclosure relates to the field of wireless communication,and in particular, to wireless communication methods, a user equipment(UE) and an eNode B (eNB).

2. Description of the Related Art

Machine-Type Communication (MTC) is an important revenue stream foroperators and has a huge potential from the operator perspective. ForMTC in coverage enhancement, basically each channel needs to do multiplerepetitions to reach for example 15 dB coverage enhancement requirement.However, since the eNB has no Channel State Information (CSI) feedbackor just obtains coarse CSI from the UE, it is difficult to guide UE'stransmissions with accurate repetition times.

SUMMARY

One non-limiting and exemplary embodiment provides an approach tooptimize the repetition times for uplink transmission.

In one general aspect, the techniques disclosed here feature a wirelesscommunication method performed by a user equipment (UE), including:transmitting transport block repetitions to an eNodeB (eNB), wherein onehybrid automatic repeat request (HARQ) process includes multiplerepetition sets of a transport block if one repetition set of thetransport block is not enough for the eNB to successfully decode thetransport block, each of the multiple repetition sets includes multiplerepetitions of the transport block, each of the multiple repetition setsis followed by a feedback channel to indicate whether the transportblock is successfully decoded by the eNB, and if the feedback channelindicates that the transport block is not successfully decoded by theeNB, the UE continues to transmit another repetition set of thetransport block.

According to the present disclosure, the repetition times for an uplinktransport block can be adapted according to the transmission condition,which saves the UE's power in addition to the time-frequency resourcessince the UE does not necessarily always transmit a large number ofrepetitions to guarantee successful decoding. In addition, the UE'srepetition times in uplink during random access can also be optimized.

It should be noted that general or specific embodiments may beimplemented as a system, a method, an integrated circuit, a computerprogram, a storage medium, or any selective combination thereof.

Additional benefits and advantages of the disclosed embodiments willbecome apparent from the specification and drawings. The benefits and/oradvantages may be individually obtained by the various embodiments andfeatures of the specification and drawings, which need not all beprovided in order to obtain one or more of such benefits and/oradvantages.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 exemplarily illustrates a HARQ process for MTC in coverage;

FIG. 2 schematically illustrates a flowchart of a wireless communicationmethod at UE side according to an embodiment of the present disclosure;

FIG. 3 schematically illustrates an exemplary HARQ process according toan embodiment of the present disclosure;

FIG. 4 schematically illustrates a flowchart of a wireless communicationmethod at eNB side according to an embodiment of the present disclosure;

FIG. 5 schematically illustrates a block diagram of a UE for wirelesscommunication according to an embodiment of the present disclosure;

FIG. 6 schematically illustrates a block diagram of an eNB for wirelesscommunication according to an embodiment of the present disclosure;

FIG. 7 schematically illustrates an example of two adjacent exemplaryHARQ processes according to an embodiment of the present disclosure;

FIG. 8 schematically illustrates another example of two adjacentexemplary HARQ processes according to an embodiment of the presentdisclosure;

FIG. 9 schematically illustrates another example of two adjacentexemplary HARQ processes according to an embodiment of the presentdisclosure;

FIG. 10 is a schematic diagram for illustrating three states of thefeedback channel according to an embodiment of the present disclosure;

FIG. 11 schematically illustrates a SPS mechanism combined with earlystopping according to an embodiment of the present disclosure;

FIG. 12 schematically illustrates an example of adjusting granularity ofthe repetition set according to an embodiment of the present disclosure;and

FIG. 13 schematically illustrates an exemplary random access processaccording to an embodiment of the present disclosure.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings, which form a part thereof. In the drawings,similar symbols typically identify similar components, unless contextdictates otherwise. It will be readily understood that the aspects ofthe present disclosure can be arranged, substituted, combined, anddesigned in a wide variety of different configurations, all of which areexplicitly contemplated and make part of this disclosure.

For MTC in coverage enhancement, since the eNB has no CSI feedback orjust obtains coarse CSI from the UE, it is difficult to guide UE'stransmissions with accurate repetition times. The eNB may indicaterelatively large or conservative repetition times (repetition number)for uplink transmission to reach for example 99% success ratio. Such abehavior costs the UE more power. FIG. 1 exemplarily illustrates a HARQprocess for MTC in coverage. As shown in FIG. 1, the eNB indicates 50repetitions (i.e., the indicated repetition number is 50) for physicaluplink shared channel (PUSCH) by the physical downlink control channel(PDCCH), the UE transmits 50 repetitions in the uplink, and the eNBfeeds back to the UE whether the PUSCH is successfully decoded byPhysical Hybrid-ARQ Indicator Channel (PHICH). However, the neededrepetition number may be only 25 (that is, the eNB can successfullydecode the PUSCH with 25 repetitions) though the eNB indicates 50repetitions due to inaccurate CSI knowledge. In this case, 25repetitions are wasted. Repetitions more than needed in uplink wastes alot of UE's power in addition to time-frequency resources. Therefore,optimizing repetition times as much as possible especially for uplinktransmission is quite important. The present disclosure provides anapproach to optimize the repetition times for uplink transmission inorder to save UE's power and time-frequency resources.

In the present disclosure, MTC may be taken as an example to describethe principle of the present disclosure; however, it is noted that thewireless communication methods disclosed in the present disclosure cannot only be applied to MTC, but also be applied to other wirelesscommunications such as other communications conforming to LTEspecifications as long as those wireless communications transmittransport block(s) in the uplink repeatedly. Accordingly, the UEs arenot limited to MTC UEs, but can be any other UEs that can perform thecommunication methods described in the present disclosure.

First Embodiment

The first embodiment of the present disclosure provides a wirelesscommunication method 200 performed by a UE, as shown in FIG. 2 whichschematically illustrates the flowchart of the wireless communicationmethod 200 according to the first embodiment of the present disclosure.The wireless communication method 200 includes a step 201 oftransmitting transport block repetitions to an eNB. According to thisembodiment, one HARQ process can include multiple repetition sets of atransport block if one repetition set of the transport block is notenough for the eNB to successfully decode the transport block, each ofthe multiple repetition sets includes multiple repetitions of thetransport block, and each of the multiple repetition sets is followed bya feedback channel to indicate whether the transport block issuccessfully decoded by the eNB. FIG. 3 schematically illustrates anexemplary HARQ process according to an embodiment of the presentdisclosure. In the exemplary HARQ process, the eNB transmits a controlchannel (e.g., PDCCH) to the UE to schedule the uplink transmission, andthen the UE transmits repetitions of a transport block to the eNB in anuplink channel (e.g., PUSCH). As can be seen from FIG. 3, repetitions ofthe transport block are divided into three repetition sets each of whichcan include for example 10 repetitions. The repetition number in eachrepetition set can be indicated in the control channel. After eachrepetition set is transmitted, a feedback channel (e.g., PHICH) istransmitted from the eNB to the UE to indicate whether the UE hassuccessfully decoded the transport block. The eNB decodes the transportblock by combining all received repetition sets of the transport blockin the current HARQ process after receiving each of the multiplerepetition sets and indicates to the UE whether the transport block issuccessfully decoded by the eNB in a feedback channel. If the feedbackchannel indicates that the transport block is not successfully decodedby the eNB, the UE continues to transmit another repetition set of thetransport block. For example, the feedback channel can be a one-bitPHICH which uses “ACK” (e.g., “1”) to indicate successful decoding anduses “NACK” (e.g., “0”) to indicate unsuccessful decoding. In theexample of FIG. 3, after receiving the first repetition set, the eNBdecodes the transport block using the first repetition set, which is notsuccessful, and thus the eNB indicates unsuccessful decoding. Then, theUE transmits the second repetition set. After receiving the secondrepetition set, the eNB decodes the transport block by combining thefirst repetition set and the second repetition set, which is notsuccessful either, and thus the eNB also indicates unsuccessfuldecoding. Then, the UE transmits the third repetition set. Afterreceiving the third repetition set, the eNB successfully decodes thetransport block by combining the first repetition set, the secondrepetition set and the third repetition set, and indicates successfuldecoding to the UE. The indication of successful decoding finishes thetransmission of this data packet. The UE may then transmit another datapacket or monitors the next control channel.

It is noted that 3 repetition sets and 10 repetitions in each repetitionset are illustrated in the above example, but the present disclosure isnot limited to that. The number of repetitions in each repetition setcan be determined according to application scenarios. For example,larger repetition number in each repetition set can be configured forworse channel conditions. Preferably, the repetition number in eachrepetition set can be indicated in a control channel related totransmission of the transport block. As for the number of repetitionsets in one HARQ process, it depends on when the transport block issuccessfully decoded by the eNB. However, the maximum repetition numberfor one transport block in one HARQ process can also be applied; forexample, the maximum repetition number of one transport block can beindicated by a control channel related to the transmission of thetransport block. The indication form of the maximum repetition numbercan be the maximum repetition times or the maximum number of repetitionsets in connection with the number of repetitions in each repetitionset. In this case, when the maximum number is reached, even though thefeedback channel indicates unsuccessful decoding, the transmission ofthe present transport block will be terminated. The definition of themaximum repetition number can increase robustness of feedback detection.

According to the first embodiment of the present disclosure, therepetition times for an uplink transport block can be adapted accordingto the transmission condition, which saves the UE's power in addition tothe time-frequency resources since the UE does not necessarily alwaystransmit a large number of repetitions to guarantee successful decoding.Taking FIG. 1 as an example, according to the first embodiment of thepresent disclosure, the UE will not always transmit 50 repetitions, buttransmit for example 10 repetitions each time and then receive afeedback. If 25 repetitions are enough for the eNB to decode thetransport block, the UE will receive a positive feedback aftertransmitting the repetitions three times, that is, totally 30repetitions are transmitted. Therefore, 20 repetitions can be savedcompared with the transmission manner in FIG. 2, such that the UE'spower can be saved. It is noted that, although a few more controlchannels may be needed according to the present disclosure, the UE'spower can be saved because uplink transmission consumes much more powerthan downlink reception (for example, referring to 3GPP Rel. 12).

At the eNB side, the first embodiment of the present disclosure providesa wireless communication method 400 performed by an eNB, as shown inFIG. 4 which schematically illustrates the flowchart of the wirelesscommunication method 400 according to the first embodiment of thepresent disclosure. The wireless communication method 400 includes astep 401 of receiving transport block repetitions transmitted from anUE, wherein one HARQ process includes multiple repetition sets of atransport block if one repetition set of the transport block is notenough for the eNB to successfully decode the transport block, each ofthe multiple repetition sets includes multiple repetitions of thetransport block, and the eNB indicates whether the transport block issuccessfully decoded by the eNB in a feedback channel by combining allreceived repetition sets of the transport block in the current HARQprocess after receiving each of the multiple repetition sets. If thefeedback channel indicates that the transport block is not successfullydecoded by the eNB, the UE continues to transmit another repetition setof the transport block for the eNB to receive, and accordingly the eNBcan receive said another repetition set of the transport block. It isnote that the above descriptions for the method 200 can also be appliedto the method 400.

In addition, the first embodiment also provides a UE and an eNB toperform the above described communication methods. FIG. 5 schematicallyillustrates a block diagram of a UE 500 for wireless communicationaccording to the first embodiment of the present disclosure. The UE 500can include a transmitting unit 501 configured to transmit transportblock repetitions to an eNB, wherein one HARQ process includes multiplerepetition sets of a transport block if one repetition set of thetransport block is not enough for the eNB to successfully decode thetransport block, each of the multiple repetition sets includes multiplerepetitions of the transport block, each of the multiple repetition setsis followed by a feedback channel to indicate whether the transportblock is successfully decoded by the eNB, and if the feedback channelindicates that the transport block is not successfully decoded by theeNB, the UE continues to transmit another repetition set of thetransport block. It is noted that the above descriptions for the method200 can also be applied to the UE 500.

The UE 500 according to the present disclosure may optionally include aCPU (Central Processing Unit) 510 for executing related programs toprocess various data and control operations of respective units in theUE 500, a ROM (Read Only Memory) 513 for storing various programsrequired for performing various process and control by the CPU 510, aRAM (Random Access Memory) 515 for storing intermediate data temporarilyproduced in the procedure of process and control by the CPU 510, and/ora storage unit 517 for storing various programs, data and so on. Theabove transmitting unit 501, CPU 510, ROM 513, RAM 515 and/or storageunit 517 etc. may be interconnected via data and/or command bus 520 andtransfer signals between one another.

Respective units as described above do not limit the scope of thepresent disclosure. According to one implementation of the disclosure,the functions of the above transmitting unit 501 may be implemented byhardware, and the above CPU 510, ROM 513, RAM 515 and/or storage unit517 may not be necessary. Alternatively, the functions of the abovetransmitting unit 501 may also be implemented by functional software incombination with the above CPU 510, ROM 513, RAM 515 and/or storage unit517 etc.

FIG. 6 schematically illustrates a block diagram of an eNB 600 forwireless communication according to the first embodiment of the presentdisclosure. The eNB 600 can include a receiving unit configured toreceive transport block repetitions transmitted from an UE, wherein oneHARQ process includes multiple repetition sets of a transport block ifone repetition set of the transport block is not enough for the eNB tosuccessfully decode the transport block, each of the multiple repetitionsets includes multiple repetitions of the transport block, the eNBindicates whether the transport block is successfully decoded by the eNBin a feedback channel by combining all received repetition sets of thetransport block in the current HARQ process after receiving each of themultiple repetition sets, and if the feedback channel indicates that thetransport block is not successfully decoded by the eNB, the UE continuesto transmit another repetition set of the transport block for the eNB toreceive. It is noted that the above descriptions for the method 400 canalso be applied to the eNB 600.

The eNB 600 according to the present disclosure may optionally include aCPU (Central Processing Unit) 610 for executing related programs toprocess various data and control operations of respective units in theeNB 600, a ROM (Read Only Memory) 613 for storing various programsrequired for performing various process and control by the CPU 610, aRAM (Random Access Memory) 615 for storing intermediate data temporarilyproduced in the procedure of process and control by the CPU 610, and/ora storage unit 617 for storing various programs, data and so on. Theabove receiving unit 601, CPU 610, ROM 613, RAM 615 and/or storage unit617 etc. may be interconnected via data and/or command bus 620 andtransfer signals between one another.

Respective units as described above do not limit the scope of thepresent disclosure. According to one implementation of the disclosure,the functions of the above receiving unit 601 may be implemented byhardware, and the above CPU 610, ROM 613, RAM 615 and/or storage unit617 may not be necessary. Alternatively, the functions of the abovereceiving unit 601 may also be implemented by functional software incombination with the above CPU 610, ROM 613, RAM 615 and/or storage unit617 etc.

In a first example of the first embodiment of the present disclosure, ifthe feedback channel indicates that the transport block is successfullydecoded by the eNB, the UE monitors the next control channel beforetransmitting repetitions of another transport block, in other words,when one transport block is successfully transmitted, the communicationproceeds to transmit another transport in another HARQ process startingwith a control channel (e.g. PDCCH). FIG. 7 schematically illustratestwo adjacent exemplary HARQ processes according to the first example ofthe first embodiment of the present disclosure. After the third feedbackchannel (e.g. PHICH) of the first HARQ process indicates successfuldecoding, the first HARQ process is finished, and the UE monitors thenext control channel to start the second HARQ process. After receivingthe control channel in the second HARQ process, the UE can transmitrepetitions of another transport block based on the scheduling of thecontrol channel in the second HARQ process. In other words, each HARQprocess is linked with a control channel for flexible scheduling whilethe UE's power can be saved by early stopping of repetitions in thefirst example.

In a second example of the first embodiment, the feedback channel forindicating successful decoding is different from the feedback channelfor indicating unsuccessful decoding. In particular, DTX (DiscontinuousTransmission) is used to indicate unsuccessful decoding (negativefeedback), in other words, the feedback channel does not transmit anysignal when the feedback channel indicates that the transport block isnot successfully decoded by the eNB. For positive feedback, i.e., whenthe feedback channel indicates that the transport block is successfullydecoded by the eNB, the function of the feedback channel can be realizedby a control channel of the next HARQ process. The reception of thecontrol channel of the next HARQ process by the UE implies that thetransport block is successfully decoded by the eNB. In other words, whenthe UE receives a control channel after transmitting a repetition set ofthe transport block, it implies that the transmission of the transportblock is successful, and the current HARQ process is finished. The UEcan transmit repetitions of another transport block according to thescheduling of the control channel just received. FIG. 8 schematicallyillustrates two adjacent exemplary HARQ processes according to thesecond example of the first embodiment of the present disclosure. Asshown in FIG. 8, in the first HARQ process, DTX follows both the firstrepetition set and the second repetition set to indicate unsuccessfuldecoding, and the third repetition set is transmitted by the UE. Aftertransmitting the third repetition set, the UE receives a controlchannel, which implies that the current transport block has beensuccessfully decoded by the eNB, and the first HARQ process is finished.The received control channel can schedule the next uplink transmissionof the UE. In this example, the control channel other than the initialcontrol channel has two functions. First, it can imply the transmissionof the last transport block is successful. Second, it can schedule thenext transmission. According to the second example, PHICH power can besaved.

In a third example of the first embodiment, if the feedback channelindicates that the transport block is successfully decoded by the eNB,the UE transmits repetitions of another transport block with theinformation in the latest control channel. In other words, the feedbackchannel is used not only to indicate whether the current transport blockis successfully decoded but also to schedule transmission of a newtransport block. FIG. 9 schematically illustrates two adjacent exemplaryHARQ processes according to the third example of the first embodiment ofthe present disclosure. As shown in FIG. 9, the first HARQ processstarts with a control channel (e.g., PDCCH) which indicates initialtransmission and possibly indicates the repetition number of eachrepetition set. Then, the UE transmits for example 10 repetitions of atransport block each time until the control channel (e.g., PHICH)indicates successful decoding (e.g., “ACK”). When the UE receives “ACK”from the control channel, it will transmit another new transport blockwithout monitoring a new control channel, and the UE can transmit thenew transport block with the information (for example, repetitionnumber, MCS, resource position, etc.) in the latest control channel.Here, the initial scheduling assignment indicated by the control channelin the first HARQ process can be used for the new transport blocktransmission. As can be seen from the third example of the firstembodiment, the control channels other the initial one can be saved inaddition to reducing the UE's power consumption.

According to the above third example of the first embodiment,flexibility may be compromised since some uplink transmissions may befar away from the initial control channel; however, based on the studyof the specifications, for MTC, it is feasible to do continuoustransmission of uplink traffic without PDCCH scheduling for each packet.

Based on analysis on 3GPP specification 36.888, there are three typicaluplink traffics for MTC UEs, which are:

-   (1) Command-response traffic (triggered reporting) between base    station and WAN module; ˜20 bytes for command (Downlink) & ˜100    bytes for response (uplink);-   (2) Exception reported by WAN module; Report (Uplink) could be ˜100    bytes with latency of 3-5 seconds from event at the WAN module;-   (3) Periodic reports or Keep alive; ˜100 bytes (Uplink).

Observing the above traffics, a UE needs to report ˜800 bits. But forMTC in coverage enhancement, to realize the largest PSD (Power SpectralDensity), generally one PRB which only carries a few bits (e.g., 16 bitsor 72 bits) is transmitted in uplink in a subframe. Therefore, to finishone report of 800 bits, the UE needs to transmit many packets. Inaddition, the MTC UE is rather static so adaptation of transmission(i.e., MCS and resource position) for each packet is not necessary.Based on the above analysis, it is feasible to do continuoustransmission of uplink traffic without PDCCH scheduling for each packet.According to the third example of the first embodiment, time-frequencyresources can be saved and the UE's power consumption can be reduced.

In a fourth example of the first embodiment, the feedback channel canindicate more than two states. If the feedback channel (e.g., PHICH)indicates that the transport block is not successfully decoded by theeNB (e.g., “NACK”), the UE continues to transmit another repetition setof the transport block; if the feedback channel indicates that thetransport block is successfully decoded by the eNB (e.g. “ACK”), the UEdirectly transmits repetitions of another transport block with theinformation in the latest control channel; if the feedback channelindicates a different state from indicating that the transport block issuccessfully or not successfully decoded by the eNB (e.g., “DTX”), theUE monitors the next control channel before the next transmission. FIG.10 is a schematic diagram for illustrating three states of the feedbackchannel according to an embodiment of the present disclosure. As shownin FIG. 10, if the control channel indicates “NACK” or “ACK”, the UEwill not monitor PDCCH and knows the current status is continuoustransmission of uplink, that is, the UE transmits another repetition setof the same transport block or transmits repetitions of anothertransport block. However, if the eNB does not transmit any signal in thecontrol channel (i.e., indicating “DTX”), the UE will monitor the nextcontrol channel (e.g., PDCCH). According to this example, UE powerconsumption can be reduced since the UE does not need to always monitora control channel.

In a fifth example of the first embodiment, an SPS mechanism is combinedwith early stopping in the first embodiment. Each SPS period may includemultiple repetition sets and feedback channels to realize earlystopping, but the UE has to wait to the next SPS period to transmit anew packet. In this example, an initial control channel schedules SPStransmission, and if the feedback channel indicates that the transportblock is successfully decoded by the eNB, the UE waits to transmitrepetitions of another transport block in the next SPS period. FIG. 11schematically illustrates an SPS mechanism combined with early stoppingaccording to an embodiment of the present disclosure. As shown in FIG.11, the initial control channel (e.g. PDCCH) can indicate SPStransmission information and possibly the number of repetitions in eachrepetition set for early stopping. The second feedback channel (e.g.,PHICH) indicates successful decoding (e.g., “ACK”) such that thetransmission of the current transport block is stopped; however, thetransmission of a new transport block should wait to the next SPS period(SPS period 2).

In a sixth example of the first embodiment, the feedback channel canalso indicate granularity of the repetition set for the nexttransmission, i.e. how many repetitions in the repetition set. Forexample, the feedback channel can include 2 bits whose four states canbe used to indicate retransmission of the current transport block withrepetition granularity 1 (for example, 10 repetitions), retransmissionof the current transport block with repetition granularity 2 (forexample, 20 repetitions), transmission of a new transport block withrepetition granularity 1, and transmission of a new transport block withrepetition granularity 2. According to this example, the eNB can realizesome flexibility to adjust granularity of the repetition set based onfor example the last transmission and can reduce active time. It isnoted that how the feedback channel indicates the granularity is notlimited herein. For example, the control channel can include two PHICHs,and the UE can interpret PHICH1 and PHICH2 as in the following table.

PHICH1 ACK NACK DTX DTX PHICH2 DTX DTX ACK NACK Interpretationtransmission retransmission transmission retransmission of a new of thecurrent of a new of the current transport transport block transporttransport block block with with repetition block with with repetitionrepetition granularity 1 repetition granularity 2 granularity 1granularity 2

FIG. 12 schematically illustrates an example of adjusting granularity ofthe repetition set according to an embodiment of the present disclosure.As shown in FIG. 12, in the first HARQ process, the granularity is 10repetitions (granularity 1) and is not changed; however, in the secondHARQ process the granularity is changed to 20 repetitions (granularity2) due to the feedback of DTX for PHICH1 and ACK for PHICH2. In thisexample, the eNB adjusts the granularity based on situation of the lasttransport block transmission, and thus the eNB can reduce feedbacks.

It is noted that the above examples of the first embodiment can becombined unless the context indicates otherwise.

Second Embodiment

The second embodiment of the present disclosure relates to a randomaccess process. FIG. 13 illustrates an exemplary random access processaccording to the second embodiment of the present disclosure. In step 1,the UE transmits repetitions (for example 10 repetitions) of message 1(preamble) to an eNB. The eNB receives and decodes the message 1, but itdoes not decode the message 1 successfully. Therefore, in step 2, theeNB feeds back “failure” in message 2 to the UE. Then, in step 3, the UEtransmits repetition of the message 1 again. The eNB receives therepetitions in step 3 and combines repetitions in step 1 and step 3 (forexample, totally 20 repetitions). At this point, the eNB successfullydecodes the message 1 and thus indicates “success” in step 4. Then, theUE proceeds with the remaining random access procedures (for example,transmit message 3 and wait for message 4). By such a procedure, theUE's repetition times in uplink during random access can be optimized.Obviously, although the message 1 is transmitted twice before successfuldecoding in the example of FIG. 13, the present disclosure is notlimited to this. The end of the transmission depends on the indicationof successful decoding, in other words, step 1 and step 3 will berepeated until the eNB indicates “success” to the UE.

Accordingly, the second embodiment of the present disclosure provides awireless communication method performed by a UE, a wirelesscommunication method performed by an eNB, a UE and an eNB. The wirelesscommunication method performed by a UE can include a transmitting stepof transmitting repetitions of a first message to an eNB for randomaccess; and a receiving step of receiving a second message fed back fromthe eNB for indicating whether the first message is successfully decodedby the eNB, wherein if the second message indicates that the firstmessage is not successfully decoded by the eNB, the transmitting stepand the receiving step are repeated until the second message indicatesthat the first message is successfully decoded by the eNB, and the eNBcombines all received repetitions of the first message from the UE todecode the first message.

The wireless communication method performed by an eNB can include areceiving step of receiving repetitions of a first message transmittedby a UE for random access; and a feedback step of feeding back a secondmessage to indicate whether the first message is successfully decoded bythe eNB, wherein if the second message indicates that the first messageis not successfully decoded by the eNB, the receiving step and thefeedback step are repeated until the second message indicates that thefirst message is successfully decoded by the eNB, and the eNB combinesall received repetitions of the first message from the UE to decode thefirst message.

A UE for wireless communication according to the second embodiment ofthe present disclosure includes: a transmitting unit configured totransmit repetitions of a first message to an eNB for random access; anda receiving unit configured to receive a second message fed back fromthe eNB for indicating whether the first message is successfully decodedby the eNB, wherein if the second message indicates that the firstmessage is not successfully decoded by the eNB, the transmitting unitand the receiving unit repeat their operations until the second messageindicates that the first message is successfully decoded by the eNB, andthe eNB combines all received repetitions of the first message from theUE to decode the first message.

An eNB for wireless communication according to the second embodiment ofthe present disclosure includes: a receiving unit configured to receiverepetitions of a first message transmitted by a UE for random access;and a feedback unit configured to feed back a second message to indicatewhether the first message is successfully decoded by the eNB, wherein ifthe second message indicates that the first message is not successfullydecoded by the eNB, the receiving unit and the feedback unit repeattheir operations until the second message indicates that the firstmessage is successfully decoded by the eNB, and the eNB combines allreceived repetitions of the first message from the UE to decode thefirst message.

It is noted that the UE and the eNB in the second embodiment of thepresent disclosure can have similar structures in FIG. 5 and FIG. 6, andthe descriptions related to FIG. 5 and FIG. 6 are also applied here. Inaddition, the first embodiment can be combined with the secondembodiment, and the detailed descriptions in the first embodiment may beapplied to the second embodiment unless the context indicates otherwise.According to the second embodiment of the present disclosure, the UE'srepetition times in uplink during random access can be optimized.

The present disclosure can be realized by software, hardware, orsoftware in cooperation with hardware. Each functional block used in thedescription of each embodiment described above can be realized by an LSIas an integrated circuit, and each process described in the eachembodiment may be controlled by LSI. They may be individually formed aschips, or one chip may be formed so as to include a part or all of thefunctional blocks. They may include a data input and output coupledthereto. The LSI here may be referred to as an IC, a system LSI, a superLSI, or an ultra LSI depending on a difference in the degree ofintegration. However, the technique of implementing an integratedcircuit is not limited to the LSI and may be realized by using adedicated circuit or a general-purpose processor. In addition, a FPGA(Field Programmable Gate Array) that can be programmed after themanufacture of the LSI or a reconfigurable processor in which theconnections and the settings of circuits cells disposed inside the LSIcan be reconfigured may be used.

It is noted that the present disclosure intends to be variously changedor modified by those skilled in the art based on the descriptionpresented in the specification and known technologies without departingfrom the content and the scope of the present disclosure, and suchchanges and applications fall within the scope that claimed to beprotected. Furthermore, in a range not departing from the content of thedisclosure, the constituent elements of the above-described embodimentsmay be arbitrarily combined.

Embodiments of the present disclosure can at least provide the followingsubject matters.

(1). A wireless communication method performed by a UE, including:

-   -   transmitting transport block repetitions to an eNB, wherein    -   one HARQ process includes multiple repetition sets of a        transport block if one repetition set of the transport block is        not enough for the eNB to successfully decode the transport        block,    -   each of the multiple repetition sets includes multiple        repetitions of the transport block,    -   each of the multiple repetition sets is followed by a feedback        channel to indicate whether the transport block is successfully        decoded by the eNB, and    -   if the feedback channel indicates that the transport block is        not successfully decoded by the eNB, the UE continues to        transmit another repetition set of the transport block.

(2). The wireless communication method according to (1), wherein

-   -   if the feedback channel indicates that the transport block is        successfully decoded by the eNB, the UE transmits repetitions of        another transport block with the information in the latest        control channel.

(3). The wireless communication method according to (1), wherein

-   -   if the feedback channel indicates that the transport block is        successfully decoded by the eNB, the UE monitors next control        channel before transmitting repetitions of another transport        block.

(4). The wireless communication method according to (1), wherein

-   -   the function of the feedback channel is realized by a control        channel of the next HARQ process when the feedback channel        indicates that the transport block is successfully decoded by        the eNB,    -   the reception of the control channel of the next HARQ process by        the UE implies that the transport block is successfully decoded        by the eNB, and    -   the feedback channel does not transmit any signal when the        feedback channel indicates that the transport block is not        successfully decoded by the eNB.

(5). The wireless communication method according to any of (1)-(3),wherein the feedback channel also indicates granularity of therepetition set for the next transmission.

(6). The wireless communication method according to any of (1)-(5),wherein the maximum repetition number of one transport block isindicated by a control channel.

(7). The wireless communication method according to (1), wherein

-   -   if the feedback channel indicates that the transport block is        successfully decoded by the eNB, the UE transmits repetitions of        another transport block with the information in the latest        control channel, and    -   if the feedback channel indicates a different state from        indicating that the transport block is successfully or not        successfully decoded by the eNB, the UE monitors next control        channel.

(8). The wireless communication method according to (1), wherein

-   -   an initial control channel schedules semi-persistent scheduling        (SPS) transmission, and    -   if the feedback channel indicates that the transport block is        successfully decoded by the eNB, the UE waits to transmit        repetitions of another transport block in the next SPS period.

(9). A wireless communication method performed by an eNB, including:

-   -   receiving transport block repetitions transmitted from an UE,        wherein    -   one HARQ process includes multiple repetition sets of a        transport block if one repetition set of the transport block is        not enough for the eNB to successfully decode the transport        block,    -   each of the multiple repetition sets includes multiple        repetitions of the transport block,    -   the eNB indicates whether the transport block is successfully        decoded by the eNB in a feedback channel by combining all        received repetition sets of the transport block in current HARQ        process after receiving each of the multiple repetition sets,        and    -   if the feedback channel indicates that the transport block is        not successfully decoded by the eNB, the UE continues to        transmit another repetition set of the transport block for the        eNB to receive.

(10). The wireless communication method according to (9), wherein if thefeedback channel indicates that the transport block is successfullydecoded by the eNB, the UE transmits repetitions of another transportblock with the information in the latest control channel.

(11). The wireless communication method according to (9), wherein

-   -   the eNB uses a control channel of the next HARQ process to        indicate that the transport block is successfully decoded by the        eNB, and    -   the feedback channel does not transmit any signal when the        feedback channel indicates that the transport block is not        successfully decoded by the eNB.

(12). The wireless communication method according to any of (9)-(11),wherein the eNB indicates the maximum repetition number of one transportblock in a control channel.

(13). The wireless communication method according to (9), wherein

-   -   if the feedback channel indicates that the transport block is        successfully decoded by the eNB, the UE transmits repetitions of        another transport block with the information in the latest        control channel, and    -   if the feedback channel indicates a different state from        indicating that the transport block is successfully or not        successfully decoded by the eNB, the UE monitors next control        channel before next transmission.

(14). The wireless communication method according to (9), wherein

-   -   the eNB schedules SPS transmission in an initial control        channel, and    -   if the feedback channel indicates that the transport block is        successfully decoded by the eNB, the UE waits to transmit        repetitions of another transport block in the next SPS period.

(15). A UE for wireless communication, including:

-   -   a transmitting unit that transmits transport block repetitions        to an eNB, wherein    -   one HARQ process includes multiple repetition sets of a        transport block if one repetition set of the transport block is        not enough for the eNB to successfully decode the transport        block,    -   each of the multiple repetition sets includes multiple        repetitions of the transport block,    -   each of the multiple repetition sets is followed by a feedback        channel to indicate whether the transport block is successfully        decoded by the eNB, and    -   if the feedback channel indicates that the transport block is        not successfully decoded by the eNB, the UE continues to        transmit another repetition set of the transport block.

(16). An eNB for wireless communication, including:

-   -   a receiving unit that receives transport block repetitions        transmitted from an UE, wherein    -   one HARQ process includes multiple repetition sets of a        transport block if one repetition set of the transport block is        not enough for the eNB to successfully decode the transport        block,    -   each of the multiple repetition sets includes multiple        repetitions of the transport block,    -   the eNB indicates whether the transport block is successfully        decoded by the eNB in a feedback channel by combining all        received repetition sets of the transport block in current HARQ        process after receiving each of the multiple repetition sets,        and    -   if the feedback channel indicates that the transport block is        not successfully decoded by the eNB, the UE continues to        transmit another repetition set of the transport block for the        eNB to receive.

(17). A wireless communication method performed by a UE, including:

-   -   transmitting repetitions of a first message to an eNB for random        access; and    -   receiving a second message fed back from the eNB for indicating        whether the first message is successfully decoded by the eNB,        wherein    -   if the second message indicates that the first message is not        successfully decoded by the eNB, the transmitting and the        receiving are repeated until the second message indicates that        the first message is successfully decoded by the eNB, and    -   the eNB combines all received repetitions of the first message        from the UE to decode the first message.

(18). A wireless communication method performed by an eNB, including:

-   -   receiving repetitions of a first message transmitted by a UE for        random access; and    -   feeding back a second message to indicate whether the first        message is successfully decoded by the eNB, wherein    -   if the second message indicates that the first message is not        successfully decoded by the eNB, the receiving and the feeding        back are repeated until the second message indicates that the        first message is successfully decoded by the eNB, and    -   the eNB combines all received repetitions of the first message        from the UE to decode the first message.

(19). A UE for wireless communication, including:

-   -   a transmitting unit that transmits repetitions of a first        message to an eNB for random access; and    -   a receiving unit that receives a second message fed back from        the eNB for indicating whether the first message is successfully        decoded by the eNB, wherein    -   if the second message indicates that the first message is not        successfully decoded by the eNB, the transmitting unit and the        receiving unit repeat their operations until the second message        indicates that the first message is successfully decoded by the        eNB, and    -   the eNB combines all received repetitions of the first message        from the UE to decode the first message.

(20). An eNB for wireless communication, including:

-   -   a receiving unit that receives repetitions of a first message        transmitted by a UE for random access; and    -   a feedback unit that feeds back a second message to indicate        whether the first message is successfully decoded by the eNB,        wherein    -   if the second message indicates that the first message is not        successfully decoded by the eNB, the receiving unit and the        feedback unit repeat their operations until the second message        indicates that the first message is successfully decoded by the        eNB, and    -   the eNB combines all received repetitions of the first message        from the UE to decode the first message.

It is noted that the technical features in the above methods can also beincorporated in the above UEs and/or eNBs. In addition, embodiments ofthe present disclosure can also provide an integrated circuit whichincludes module(s) for performing the step(s) in the above respectivecommunication methods. Further, embodiments of the present can alsoprovide a computer readable storage medium having stored thereon acomputer program containing a program code which, when executed on acomputing device, performs the step(s) of the above respectivecommunication methods.

What is claimed is:
 1. A wireless communication method performed by auser equipment (UE), comprising: transmitting transport blockrepetitions to an eNodeB (eNB), wherein one hybrid automatic repeatrequest (HARQ) process comprises multiple repetition sets of a transportblock if one repetition set of the transport block is not enough for theeNB to successfully decode the transport block, each of the multiplerepetition sets comprises multiple repetitions of the transport block,each of the multiple repetition sets is followed by a feedback channelto indicate whether the transport block is successfully decoded by theeNB, and if the feedback channel indicates that the transport block isnot successfully decoded by the eNB, the UE continues to transmitanother repetition set of the transport block.
 2. The wirelesscommunication method according to claim 1, wherein if the feedbackchannel indicates that the transport block is successfully decoded bythe eNB, the UE transmits repetitions of another transport block withthe information in the latest control channel.
 3. The wirelesscommunication method according to claim 1, wherein if the feedbackchannel indicates that the transport block is successfully decoded bythe eNB, the UE monitors next control channel before transmittingrepetitions of another transport block.
 4. The wireless communicationmethod according to claim 1, wherein the function of the feedbackchannel is realized by a control channel of the next HARQ process whenthe feedback channel indicates that the transport block is successfullydecoded by the eNB, the reception of the control channel of the nextHARQ process by the UE implies that the transport block is successfullydecoded by the eNB, and the feedback channel does not transmit anysignal when the feedback channel indicates that the transport block isnot successfully decoded by the eNB.
 5. The wireless communicationmethod according to claim 1, wherein the feedback channel also indicatesgranularity of the repetition set for the next transmission.
 6. Thewireless communication method according to claim 1, wherein the maximumrepetition number of one transport block is indicated by a controlchannel.
 7. The wireless communication method according to claim 1,wherein if the feedback channel indicates that the transport block issuccessfully decoded by the eNB, the UE transmits repetitions of anothertransport block with the information in the latest control channel, andif the feedback channel indicates a different state from indicating thatthe transport block is successfully or not successfully decoded by theeNB, the UE monitors next control channel.
 8. The wireless communicationmethod according to claim 1, wherein an initial control channelschedules semi-persistent scheduling (SPS) transmission, and if thefeedback channel indicates that the transport block is successfullydecoded by the eNB, the UE waits to transmit repetitions of anothertransport block in the next SPS period.
 9. A wireless communicationmethod performed by an eNB, comprising: receiving transport blockrepetitions transmitted from an UE, wherein one HARQ process comprisesmultiple repetition sets of a transport block if one repetition set ofthe transport block is not enough for the eNB to successfully decode thetransport block, each of the multiple repetition sets comprises multiplerepetitions of the transport block, the eNB indicates whether thetransport block is successfully decoded by the eNB in a feedback channelby combining all received repetition sets of the transport block incurrent HARQ process after receiving each of the multiple repetitionsets, and if the feedback channel indicates that the transport block isnot successfully decoded by the eNB, the UE continues to transmitanother repetition set of the transport block for the eNB to receive.10. The wireless communication method according to claim 9, wherein ifthe feedback channel indicates that the transport block is successfullydecoded by the eNB, the UE transmits repetitions of another transportblock with the information in the latest control channel.
 11. Thewireless communication method according to claim 9, wherein the eNB usesa control channel of the next HARQ process to indicate that thetransport block is successfully decoded by the eNB, and the feedbackchannel does not transmit any signal when the feedback channel indicatesthat the transport block is not successfully decoded by the eNB.
 12. Thewireless communication method according to claim 9, wherein the eNBindicates the maximum repetition number of one transport block in acontrol channel.
 13. The wireless communication method according toclaim 9, wherein if the feedback channel indicates that the transportblock is successfully decoded by the eNB, the UE transmits repetitionsof another transport block with the information in the latest controlchannel, and if the feedback channel indicates a different state fromindicating that the transport block is successfully or not successfullydecoded by the eNB, the UE monitors next control channel before nexttransmission.
 14. A wireless communication method performed by a UE,comprising: transmitting repetitions of a first message to an eNB forrandom access; and receiving a second message fed back from the eNB forindicating whether the first message is successfully decoded by the eNB,wherein if the second message indicates that the first message is notsuccessfully decoded by the eNB, the transmitting and the receiving arerepeated until the second message indicates that the first message issuccessfully decoded by the eNB, and the eNB combines all receivedrepetitions of the first message from the UE to decode the firstmessage.
 15. A wireless communication method performed by an eNB,comprising: receiving repetitions of a first message transmitted by a UEfor random access; and feeding back a second message to indicate whetherthe first message is successfully decoded by the eNB, wherein if thesecond message indicates that the first message is not successfullydecoded by the eNB, the receiving and the feeding back are repeateduntil the second message indicates that the first message issuccessfully decoded by the eNB, and the eNB combines all receivedrepetitions of the first message from the UE to decode the firstmessage.